FIGS. 30A and 30B show an example of a small LCD board 1 suitable for equipment such as mobile phones. The LCD board 1 has a liquid crystal display section 1a and an electrode section 1b having ends of driver voltage supply lines 2 disposed along one side edge of the board. On an FPC board 3 that is mounted on the LCD board 1, a driver circuit is formed by an IC 4, chip components 5 and the like. One side edge of the FPC board 3 is provided with a electrode section 3a in which ends of driver voltage supply lines 7 for the driver circuit are disposed. The electrode section 3a is fixed onto the electrode section 1b of the LCD board 1 with anisotropic conductive film tape (ACF tape), anisotropic conductive paste (ACP) or the like, and the driver voltage supply lines 2 of the LCD board 1 are electrically connected to corresponding driver voltage supply lines 7 of the FPC board 3.
In recent years, a function of displaying a color image has been required for this type of LCD board 1 and, accordingly, a conspicuous increase in a number of the driver voltage supply lines 2, 7 has been demanded. A decrease in a pitch of the driver voltage supply lines 2, 7 would allow the number of the driver voltage supply lines 2, 7 to be increased without causing increases in sizes of the LCD board 1 and the FPC board 3. However, since the decrease in pitch is limited to the order of 50 μm, it is difficult to achieve the increase in the number of the driver voltage supply lines 2, 7 required for displaying the color image and the like only by the decrease in the pitch.
For example, if the LCD board 1 has a quadrangular shape with a length of a side of about 30 mm, the pitch of the driver voltage supply lines 2, 7 is about 50 μm, and the number of the driver voltage supply lines 2 is about 768 at a maximum, then a length required for achievement of the number of the driver voltage supply lines 2 is 38.4 mm (50 (μm) multiplied by 768 (lines)), which is larger than the length of a side of the LCD board 1 and cannot be fulfilled.